164 PEACH LEAF CURL'. ITS NATURE AND TREATMENT. 



for pound of lime in their composition, and also that the amount of 

 lime may be much less in the copper than in the sulphur sprays and 

 still maintain the enduring qualities. It is likewise the opinion of the 

 writer that where a winter spray of copper and lime has proved of 

 poorer weathering quality than is desirable in a given climate, the cop- 

 per should be increased as well as the lime when greater resistance to 

 weathering is sought. In other words, while the increase of lime 

 enhances the weathering qualities of the spray, it also has a tendency 

 to retard or obscure the action of the copper it contains, unless the 

 latter is increased somewhat in proportion to the increase of lime. 



THE CORROSIVE ACTION OF THE SPRAYS. 



As the present use of sprays has been limited to their winter appli- 

 cation, the notes on their corrosive action relate largely to the action 

 upon dormant trees or upon the vegetation immediately following 

 the commencement of spring growth. In each case these remarks 

 relate to the use of sprays upon peach trees, which are known to be 

 among the most tender deciduous fruit trees commonly grown in the 

 temperate zone. 



The sulphur sprays of the greater strengths used in these experi- 

 ments caused in many cases the loss of some of the tiner and weaker inner 

 growth of the trees. This is more apt to be the case, it is believed, 

 when the spray is applied shortly before growth begins in the spring. 

 Where very strong sprays of this class are to be used, it is well to 

 apply them comparatively early in the dormant period, say four weeks 

 earlier than the copper sprays. Sprays having not more than 10 pounds 

 of sulphur to 45 gallons of spray may be used with little danger up 

 to within four weeks of the swelling of the buds. 



There is no danger of injuring twigs or buds with the copper sprays if 

 properly prepared and applied before the buds have opened. Well- 

 made Bordeaux mixture may be used even as late as the opening of the 

 first blossom buds. The ammoniacal copper carbonate may also be safely 

 used to a late date, and both may be again applied, if desired, after the 

 trees have passed out of bloom. The simple solution of copper sul- 

 phate and the eau celeste may be safely used to within a week of the 

 opening of peach buds, but they should never be used upon the foliage 

 of the tree. Modified eau celeste is less corrosive than the eau celeste, 

 and may be used until the first buds begin to open, but from observa- 

 tion in other classes of spray work it is believed to be unsafe to apply 

 this spray to the leaves of the peach. 



The injurious action of the sulphur sprays when combined with Bor- 

 deaux mixture is fairly to be compared with the action of the sulphur 

 sprays alone when. containing equal amounts of sulphur. 



The spray composed of iron sulphate and lime is more apt to injure 

 tender shoots and buds than the Bordeaux mixture, and such a spray 

 can not be recommended for use upon foliage. 



